transaction.py

from collections import OrderedDict

import binascii

import Crypto
import Crypto.Random
from Crypto.Hash import SHA256
from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5

import json

import requests
from flask import Flask, jsonify, request, render_template


class Transaction:

	def __init__(self, sender_address, recipient_address, amount,
				 transaction_inputs, transaction_outputs=[]):
		##set

		#self.sender_address: To public key του wallet από το οποίο προέρχονται τα χρήματα
		self.sender_address = sender_address

		#self.receiver_address: To public key του wallet στο οποίο θα καταλήξουν τα χρήματα
		self.recipient_address = recipient_address
		
		#self.amount: το ποσό που θα μεταφερθεί
		self.amount = amount

		#self.transaction_inputs: λίστα από Transaction Input
		self.transaction_inputs = transaction_inputs
		
		self.transaction_outputs = []
		
		#self.signature : Υπογραφή που δημιουργήθηκε από κάποιο private key
		self.signature = None
		
		#self.transaction_id: το hash του transaction
		self.transaction_id = SHA256.new(self.to_json().encode()).hexdigest()

		#self.transaction_outputs: λίστα από Transaction Output
		self.transaction_outputs = transaction_outputs

	def __str__(self):
		string = 'TRANSACTION: ' + self.transaction_id + '\n'
		string += 'Sender:    ' + self.sender_address + '\n'
		string += 'Recipient: ' + self.recipient_address + '\n'
		string += 'Amount:    ' + str(self.amount) + '\n'
		return string
	
	def to_json(self):
		transaction = {'sender_address' : self.sender_address,
                        'recipient_address' : self.recipient_address,
						'amount' : self.amount,
                        'transaction_inputs' : str(self.transaction_inputs),
                        'transaction_outputs' : str(self.transaction_outputs),
        }
		return json.dumps(transaction)

	def sign_transaction(self, private_key):
		"""
		Sign transaction with private key
		"""		
		transaction_bytes = self.to_json().encode()
		hash_object = SHA256.new(transaction_bytes)
		key = RSA.importKey(private_key)
		self.signature = PKCS1_v1_5.new(key).sign(hash_object)

	def verify_signature(self, public_key):
		transaction_bytes = self.to_json().encode()
		hash_object = SHA256.new(transaction_bytes)
		key = RSA.importKey(public_key)
		try:
			PKCS1_v1_5.new(key).verify(hash_object, self.signature)
			print('The signature is valid!')
			return True
		except (ValueError, TypeError):
			print('The signature is not valid')
			return False
	
# key_object = RSA.generate(2048)
# public_key = key_object.publickey().export_key()
# public_key1 = public_key.decode().encode()
# print(public_key1)
# private_key = key_object.export_key()
# trans = Transaction('0', '192.168.0.5:5000', 100, [])
# trans.sign_transaction(private_key)
# trans.verify_signature(public_key1)